Worcestershire beat Gloucestershire to open a 43-point lead in Division Two, while Kent got back in the promotion race.
Daryl Mitchell hit 102 not out as Division Two leaders Worcestershire reached 299-7 on day one against Gloucestershire.
Sam Northeast's 91 helped Kent to 351-7 on day one against Surrey, while Derbyshire's seamers enjoyed themselves.
Tom Westley's century destroyed Kent to help table-topping Essex claim a 63-run NatWest t20 Blast victory.
Acting captain Alfonso Thomas claimed two wickets in the final over as Somerset beat Gloucestershire by seven runs.
Sam Northeast's first century of the season helped Kent cruise to a six-wicket win against Leicestershire at Grace Road.
Hampshire seamer James Tomlinson enjoyed a moment to remember against Gloucestershire in Division Two.
Mitchell Claydon claimed his best figures for Kent as Leicestershire were bowled out for 217 on day one at Grace Road.
Essex stayed top of the South Group with a five-wicket victory against Surrey, while Hampshire and Gloucs also won.
Jason Roy continued his good form as Surrey chased down a target of 156 to beat Kent by eight wickets in the T20 Blast.
Saeed Ajmal posted match figures of 12-140 as Worcestershire claimed a 249-run victory over Glamorgan at New Road.
With England set to announce their Test squad to face India, we look at five potential spin options.
Mark Pettini's perfectly paced half-century helped Essex back to top spot and handed Somerset a fifth defeat in eight.
Kent escaped with a warning from an ECB pitch panel after their 10-wicket victory over Derbyshire at Canterbury.
Gary Wilson impressed with an unbeaten 160 to put Surrey in a strong position on day two against Leicestershire.
Glamorgan openers Jacques Rudolph and Will Bragg made hay in the Bristol sunshine against Gloucestershire.
Kevin Pietersen's Surrey beat Glamorgan but he once again struggled to make an impact in Friday's encounter.
James Vince cracked 240 as Hampshire thrashed Essex by 470 runs inside three days to boost their promotion hopes.
Surrey and Hampshire took complete control of their respective Division Two fixtures on Monday.
Hampshire finished the first day in the ascendancy after making 286 all out and then reducing Essex to 55-2 at stumps.
England off-spinner James Tredwell has joined Sussex on a month’s loan from Kent to play in the LV= County Championship.
Somerset secure a dramatic one-run win over leaders Hampshire while Glamorgan and Kent shared the spoils in thriller.
Ravi Bopara hit an unbeaten 81 from 44 balls as Essex beat Kent by six wickets in the NatWest T20 Blast South Division.
Saeed Ajmal put promotion rivals Hampshire in a spin to boost Worcestershire’s chances of forcing a victory at New Road.
Surrey finished the opening day with a first-innings lead at Bristol, while Worcestershire are on top against Hampshire.